Novel deoxycholic acid alkylamide-phenylurea-derived organogelators

2010

Abstract Three monomeric and three dimeric deoxycholic acid (DCA) alkylamido-phenylurea derivatives are designed based on known gelators and are synthesized and characterized by 1 H and 13 C NMR spectroscopy, ESI-TOF mass spectrometry, and elemental analyses. Among them, a monomeric derivative forms supramolecular gels in CHCl 3 and chlorobenzene, whereas a dimeric derivative gels THF and higher 1-alkanols containing 7–10 carbons. The morphologies of their xerogels are studied by scanning electron microscopy (SEM). No signature of macroscopic chirality of the gels is visible.

Noncovalent Saccharide Recognition by Means of a Tetrakis(bile acid)-Porphyrin Conjugate: Selectivity, Cooperation, and Stability

2010

Molecular recognition of Glu, Glc 2 -Glc 6 and Mal 3 by a tetrakis(bile acid)―porphyrin conjugate has been studied by using ESI-FTICR mass spectrometry. The bile acid conjugate was observed to form 1:1 noncovalent complexes with saccharides. The conjugate was found to have size-selectivity towards saccharides with three or more glucose residues. The Glc 3 and Glc 4 also formed kinetically the most stable complexes. The electron capture dissociation (ECD) experiments revealed that in complexation of an oligosaccharide three glucose residues interact with the bile acid conjugate, whereas additional glucose residues are susceptible to fragmentation. The ECD results also showed the significance…

UV-induced solvent free synthesis of truxillic acid–bile acid conjugates

2009

The solvent free UV-induced [2 + 2] intermolecular cycloaddition of two molecules of 3α-cinnamic acid ester of methyl lithocholate produced in 99% yield of α- and e-truxillic acid-bis(methyl lithocholate) isomers, which possess two structurally different potential binding sites. A prerequisite for this effective solid state reaction is a proper self-assembled crystal structure of the starting conjugate crystallized from acetonitrile. The crystallization of cinnamic acid ester of methyl lithocholate from acetonitrile produces two different crystalline forms (polymorphs), which is the reason for the solid state formation of two isomers of truxillic acid-bis(methyl lithocholate).

Novel bile acid conjugates with aryl/alkenyl linker: Synthesis and characterization

2008

Abstract Eight potential precursors for the design of bile acid derived receptors viz. 2,6-bis[dimethyl(3α-hydroxy-5β-cholan-24-amidoethyl)ammonio-methyl]naphthalene dibromide (1), 3,3′-bis[dimethyl(3α-hydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]biphenyl dibromide (2), 3,3′-bis[dimethyl(3α,7α,12α-trihydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]biphenyl dibromide (3), 4,4′-bis[dimethyl(3α-hydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]stilbene dibromide (4), 4,4′-bis[dimethyl(3α,7α,12α-trihydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]stilbene dibromide (5), allyl-dimethyl(3α,7α,12α-trihydroxy-5β-cholan-24-amidoethyl)ammonium bromide (6), 1,4′-bis[dimethyl(3α-hydroxy-5β-cholan-24-amidoethyl…

Synthesis, Characterization, and Saccharide Binding Studies of Bile Acid − Porphyrin Conjugates

2007

Synthesis and characterization of bile acid-porphyrin conjugates (BAPs) are reported. Binding of saccharides with BAPs in aqueous methanol was studied by monitoring changes in the visible absorption spectral of the porphyrin-moieties. Although these studies clearly showed absorbance changes, suggesting quite high if non-selective binding, the mass spectral studies do not unambiguously support these results.

Novel Porphyrin-cholic Acid Conjugates as Receptors for Biologically Important Anions

2007

Synthesis and characterization of lithocholic acid derived dipyrromethanes: precursors for pyrrole-steroidal macrocycles

2004

Abstract Three steroidal dipyrromethanes, 3,3,24,24-tetrakis(pyrrol-2-yl)-5β-cholane 1 , 3,3-bis(pyrrol-2-yl)-5β-cholan-24-oic acid 2 , and methyl 3,3-bis(pyrrol-2-yl)-5β-cholan-24-oate 3 , have been prepared from 3α-hydroxy-5β-cholan-24-oic acid (lithocholic acid) 4 in good overall yields. The structures of 1 – 3 have been fully characterized by 1 H, 13 C, PFG DQF 1 H– 1 H COSY, 1 H– 1 H ROESY, 13 C DEPT-135, PFG 1 H– 13 C HMQC, PFG 1 H– 13 C HMBC, and PFG 1 H– 15 N HMBC NMR spectra. Their molecular weights and compositions have been determined by ESI-TOF and EI mass spectra, and elemental analyses. The energetically optimised geometry and isotropic 13 C NMR chemical shifts of 3,3,24,24-te…

Novel Porphyrin-Cholic Acid Conjugates as Receptors for Biologically Important Anions

2005

A series of novel receptors showing high binding affinity in aqueous media for biologically important anions are reported. These naturally chromophoric porphyrin-based receptors contain cholic acids connected via quaternary alkyl ammonium amido linkages.

3α-Hydroxy-N-(3-hydroxypropyl)-5β-cholan-24-amide

2009

The title compound, C27H47NO3, is a (3-hydroxypropyl)amide derivative of naturally occurring enantiopure lithocholic acid (3-hydroxy-5-cholan-24-oic acid). The molecule contains four fused rings: three six-membered rings in chair conformations and one five-membered ring in a half-chair form. The two terminal six-membered rings are cis-fused, while other rings are trans-fused. The structure contains an intramolecular O—H O hydrogen bond and a similar hydrogen-bond framework to the corresponding deoxycholic and chenodeoxycholic acid derivatives. Intermolecular O— H O and N—H O interactions are also present in the crystal. This compound seems to have at least two polymorphic forms from a compa…

Synthesis and characterization of novel bile-acid – heteroaryl conjugates with N-(2-aminoethyl)amido linker

2008

Abstract Four novel bile acid conjugates N-[2-([2,2′]-bithiophen-5-ylmethyl)aminoethyl]-3α-hydroxy-5β-cholan-24-amide (1), N-[2-([2,2′]-bithiophen-5-ylmethyl)aminoethyl]-3α,7α,12α-trihydroxy-5β-cholan-24-amide (2), N-[2-(1H-pyrrol-2-ylmethyl)aminoethyl]-3α-hydroxy-5β-cholan-24-amide (3), N-[2-(pyridin-2-ylmethyl)aminoethyl]-3α-hydroxy-5β-cholan-24-amide (4) have been synthesized in moderate to good yields, and their structures have been characterized by 1H, 13C, 13C DEPT-135, PFG 1H,13C HMQC, and PFG 1H,13C HMBC NMR spectra. Their molecular weights and elemental compositions have been determined by ESI-TOF mass spectrometry and elemental analyses. Crystal structure of 1 characterized with o…

Self-Organization of 2-Acylaminopyridines in the Solid State and in Solution

2010

Aggregation of 2-acylaminopyridines and their 6-methyl derivatives in chloroform solution was studied by (1)H, (13)C, and (15)N NMR spectroscopies. The results were compared with (13)C and (15)N CPMAS NMR and IR spectral as well as with X-ray structural data. Intermolecular interactions in solution and in solid state were found to have a similar nature. Relatively strong N(amide)-H···N(pyridine) intermolecular hydrogen bonds enable dimerization to take place. Steric interactions in N-pivaloyl- and N-1-adamantylcarbonyl as well as that caused by the 6-methyl group hinder formation of the dimeric aggregates stabilized by the N(amide)-H···N(pyridine) intermolecular hydrogen bonds. In general, …

Bile acid alkylamide derivatives as low molecular weight organogelators: systematic gelation studies and qualitative structural analysis of the syste…

2011

A series of amino- and hydroxyalkyl amides of bile acids have been synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), (1)H and (13)C nuclear magnetic resonance spectroscopy (NMR), as well as electrospray ionization mass spectrometry (ESI-MS) measurements. The ability of the synthesized molecules to promote gel formation was systematically investigated. Out of 396 combinations formed by 11 compounds and 36 different solvents, 22 gel-containing systems were obtained with 1% (w/v) gelator concentration. Apart from one exception, the gelator compounds were lithocholic acid derivatives. This challenges the general trend of bile acid-based physical gelators, accordin…

Synthesis of Both Ionic Species of Ammonium Dithiocarbamate Derived Cholic Acid Moieties

2011

The reaction of 3-aminopropylamide of cholic acid with CS2 produced a bile acid derivative of dithiocarbamic acid which further formed an ammonium salt with another molecule of 3-aminopropylamide of cholic acid. The cationic 3-ammonium propylamide of cholic acid did not react further with CS2 and the formed salt was stable in the reaction mixture, even when excess CS2 was used. When the reaction was carried out in the presence of aqueous sodium hydroxide, only the bile acid derivative of sodium dithiocarbamate was formed. The dithiocarbamate derivatives were characterized by 1H- and 13C-NMR spectroscopy and ESI-TOF mass spectrometry.

Porphyrin-bile acid conjugates: from saccharide recognition in the solution to the selective cancer cell fluorescence detection.

2008

This paper describes the preparation and use of conjugates of porphyrins and bile acids as ligands to bind to tumor expressed saccharides. Bile acid-porphyrin conjugates were tested for recognition of saccharides that are typically present on malignant tumor cells. Fluorescence microscopy, in vitro PDT cell killing, and PDT of subcutaneous 4T1 mouse tumors is reported. High selectivity for saccharide cancer markers and cancer cells was observed. This in vivo and in vitro study demonstrated high potential use for these compounds in targeted photodynamic therapy.

NMR and quantum chemical studies on association of 2,6-bis(acylamino)pyridines with selected imides and 2,2′-dipyridylamine

2010

Association constants of 2,6-bis(alkylcarbonylamino)pyridines (alkyl = methyl or ethyl) and their perfluoroalkyl analogues with succin- and maleimide as well as with 2,2′-dipyridylamine (complementary DAD and ADA hydrogen bonding motifs are responsible for formation of the associates) have been determined by NMR titrations and quantum chemical calculations. Interactions of 2,6-bis(alkylcarbonylamino)pyridines with imides differ by character from these of perfluoroalkyl analogues. Such large difference was not observed for the 2,2′-dipyridylamine associates. Since fluorine atoms cause carbonylamino groups to be stronger hydrogen bond donors, perfluorinated species of this type were found to …

Design, synthesis and spectral studies of novel bile acid-arene conjugates: Trans to cis isomerization of azobenzene core controlled by bile acid hyd…

2008

Abstract Four bile acid-arene conjugates, 1,4-bis[dimethyl(3α,7α,12α-trihydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]benzene dibromide ( 1 ), 1,3,5-tris[dimethyl(3α,7α,12α-trihydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]benzene tribromide ( 2 ), bis{4-[dimethyl(3α,7α,12α-trihydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]phenyl}diazene dibromide ( 3 ), and bis{4-[dimethyl(3α-hydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]phenyl}diazene dibromide ( 4 ), have been synthesized in good yields, and their structures have been characterized by 1 H, 13 C, 13 C DEPT-135, PFG 1 H, 13 C HMQC, PFG 1 H, 13 C HMBC, and PFG 1 H, 15 N HMBC NMR spectra. Their molecular weights and elemental compositions have…

1H-, 13C-, and 15N-NMR and ESI-TOF+ MS studies of a supramolecular complex of silver(I) and a cholaphane

2003

A novel application of the mixed anhydride procedure for synthesising lithocholic acid piperazine diamide, an important intermediate in designing bile acid-based supramolecular host molecules, is reported. The synthesis of a thiophene-containing cholaphane with transition metal complexation ability and 1H-, 13C-, and 15N-NMR as well as ESI-TOF+ MS spectral characterisation of the ligand and its Ag(I) complex are included. The coordination of the Ag(I) ion as well as an ability of the cholaphane to recognise Ag(I) ion over alkali metal ions, especially potassium ion, is discussed. The possible medical applications are also presented.

Synthesis of Both Ionic Species of Ammonium Dithiocarbamate Derived Cholic Acid Moieties

2011

The reaction of 3-aminopropylamide of cholic acid with CS₂ produced a bile acid derivative of dithiocarbamic acid which further formed an ammonium salt with another molecule of 3-aminopropylamide of cholic acid. The cationic 3-ammonium propylamide of cholic acid did not react further with CS₂ and the formed salt was stable in the reaction mixture, even when excess CS₂ was used. When the reaction was carried out in the presence of aqueous sodium hydroxide, only the bile acid derivative of sodium dithiocarbamate was formed. The dithiocarbamate derivatives were characterized by ¹H- and ¹³C-NMR spectroscopy and ESI-TOF mass spectrometry. peerReviewed